Top-Hat Diffuser for Laser Projection Light Uniformity
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Solution Overview
Problem
Current projection image display devices face inefficiencies in light utilization due to non-uniform intensity distributions, which affect the light emission efficiency of phosphor wheels and overall image quality.
Innovation Solution
A projection image display device incorporating a laser light source, a top-hat diffusing element to provide a top-hat intensity distribution, a light homogenization element to homogenize the light intensity, and a light modulating element to project the modulated light, enhancing light utilization efficiency by ensuring uniform illumination of the phosphor wheel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional light sources with non-uniform intensity distribution are used, then the device structure is simpler, but the light emission efficiency of phosphor wheel decreases
Solution Approach 1:
The patent applies preliminary action by pre-shaping the excitation light intensity distribution into a top-hat profile using optical elements (such as aspheric lenses or diffractive optical elements) before the light reaches the phosphor wheel. This pre-conditioning of the light ensures uniform phosphor excitation from the outset, maximizing light emission efficiency without requiring complex post-processing optical systems.
Solution Approach 2:
The patent implements local quality by creating a specific top-hat intensity distribution pattern in the excitation light, where the central region has high and uniform intensity while the edges are controlled. This localized intensity optimization ensures that the phosphor wheel receives precisely the right amount of excitation light across its active area, improving overall emission efficiency.
2Productivity
If non-uniform excitation light distribution is used, then the optical system is simpler, but the light utilization efficiency decreases
Solution Approach 1:
The patent applies parameter changes by transforming the intensity distribution parameter of the excitation light from a conventional Gaussian or non-uniform profile to a controlled top-hat distribution. This parameter transformation is achieved through optical elements that modify the spatial intensity characteristics, ensuring uniform phosphor excitation and maximizing light utilization efficiency.
3Manufacturing precision
If conventional illumination methods are used, then the device structure is simpler, but the image quality deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-conditioning the excitation light into a top-hat intensity distribution before it interacts with the phosphor wheel. This pre-shaping ensures that the generated light has uniform characteristics from the source, which directly translates to improved image quality in the projected output without requiring additional complex correction optics.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution significantly enhances light emission efficiency and utilization, resulting in improved image quality by ensuring uniform illumination and efficient light modulation, thereby increasing the overall performance of the projection image display device.
Implementation Method 1
a laser light source which emits excitation light; a light emitter which emits light in response to the excitation light
Implementation Method 2
a top-hat diffusing element which diffuses and provides the excitation light with a top-hat intensity distribution
Data Source
AI summary
A projection image display device includes: laser diodes which emit excitation light; a top-hat diffusing element which diffuses and provides the excitation light with a top-hat intensity distribution; a phosphor which emits light when illuminated by the excitation light diffused by the top-hat diffusing element; an integrator rod which homogenizes the light emitted by the phosphor; DMDs which modulate the light homogenized by the integrator rod; and a projector which projects the light modulated by the DMDs.